The other side - two guys happily driving along, Volvo comes round the corner, doesn't leave room, smashes their expensive heated mirror and just drives off, no attempt to stop. Both infuriated, get buzzed up by the chase of this arrogant miscreant, and vent with a volley of insults once they arrive.
I like the comment about maybe they have calmed down now, and I also suggest 50/50 of a sort (remembering that some mirrors can cost a fortune these days) and if he doesn't play ball then pointing out that two guys threatening a lone woman might give him a lot more costs than half a mirror - his choice. Also point out that next time they phone her if they are anything other than polite it will be considered a continuation of the threatening.
did she get any ID like a number plate?